Pulmonary artery pressure (PAP) measurements are known in the art and have been used for a number of years to aid in the diagnosis of cardiac and pulmonary diseases. A PAP measurement may be obtained through an invasive procedure, such as using a pulmonary arterial catheter (e.g., Swan-Ganz catheter). A PAP estimation may also be obtained through a noninvasive procedure, for example, using Doppler Echocardiography, in order to estimate the PAP via known-in-the-art ultrasound techniques. In addition, methods using heart sounds analysis have also been proposed. For example, see U.S. Pat. No. 6,368,283 to Xu et al., entitled “Method and apparatus for estimating systolic and mean pulmonary artery pressures of a patient.”
Invasive procedures, however, are typically uncomfortable and problematic for the patient. Pulmonary artery catheterization, for example, even in skilled hands, may carry various risks and complications.
Doppler Echocardiography, may not be efficacious in the absence of a Doppler-detectable tricuspid valve regurgitation. Furthermore, the values of systolic PAP are only approximate because a clinical estimation of the right atrial (RA) pressure is typically necessary. This may be a potential source of error in the estimation of the real PAP in a patient. Furthermore, a good acoustic window and satisfactory flow tracing are typical factors used to adequately locate the tricuspid regurgitant jet. These factors, however, may be suboptimal in persons with pulmonary hyperinflation, or in those persons who are obese, because of poor transmission of sound waves.
Both conventional invasive and noninvasive procedures typically require highly skilled personnel (i.e., physicians or technicians) as well as the utilization of expensive equipment. Cardiac catheterization may also require use of a suitably equipped operating room, with attending operating room personnel.